1. Field of the Invention
The present invention relates to a network control system mainly comprising a managing device (typically a server) that provides various kinds of services, separate devices (typically, clients) that request various kinds of services and a repeater (typically, a hub) that interconnects the managing device and separate devices. The present invention also relates to a network apparatus, a repeater; and a connecting apparatus.
More particularly, the present invention pertains to a technique implemented in a client-server local area network (usually abbreviated to xe2x80x9cLANxe2x80x9d) control system. The technique is intended to reduce electric power that is consumed by a client and a hub in the case in which, in the nighttime or when the power source of a client is turned off, a power source switch on the client is automatically turned on by means of a special packet, which in sent from a server and generally called xe2x80x9cwake-up packet,xe2x80x9d in order to perform various kinds of maintenance on the client under remote control from the server.
2. Description of the Related Art
Herein, in an effort to clarify problems underlying the related arts, a configuration of a convectional LAN control system and the operations performed by the LAN control system will be explained with reference to FIG. 1 to FIG. 3 that will be described later in xe2x80x9cBrief Description of the Drawings.xe2x80x9d
A block diagram schematically showing the configuration of a conventional client-server LAN control system is illustrated in FIG. 1.
Herein, what is referred to as a xe2x80x9cserverxe2x80x9d is hardware or software having the function of providing various services to other machines (that is, separate devices each including hardware or software and each being called, typically, a client) in a network configuration. Referring to FIG. 1, a server is a device S having hardware and software integrated thereinto. From a functional viewpoint, tho server often manages programs, databases, printers, and a network. On the other hand, a server may be defined as a device that receives requests. By the way, what is referred to as a xe2x80x9cclientxe2x80x9d is a device that requests tho server to render services. In the client-server LAN control system, the client is often realized as a personal computer operated by a user. Heroin, a term xe2x80x9cclient-server LAN (or a client-server model)xe2x80x9d defines a processing form in which the roles to be filled by computers interconnected over a LAN are clarified, that is, one of basic models of distributed processing. The client-server LAN accommodates a server that provides specified features and clients that utilize the features. Normally, the clients are realized as users"" personal computers, and the server is realized as a computer having a high processing ability. Services provided by the server are often arithmetic operations that require a database or that must be performed at high speed. On the other hand, the server manages the whole of a client-server LAN control system.
As is obvious from the block diagram of FIG. 1, in the typical client-server LAN control system, the server S (managing device) that manages the whole of the system exists on a basic LAN (BL). A hub H in connected to the basic LAN in the form of a chip. The clients C (separate devices) are realized as personal computers (usually, simply called computers) and are connected on the basic LAN via the hub H. The hub H serves as a repeater for connecting a plurality of clients to a LAN. The protocol which the clients C and hub H use is Ethernet 10 Base-T (transmission rate: 10 megabits per sec (Mbps)) or Ethernet 100 Base-TX (transmission rate: 100 Mbps).
An alternating current (ac) power source cable AD led out from each client C is plugged into a mains ac outlet AS formed on a wall or the like. Electric power is distributed to each client through the ac outlet AS. Normally, the ac power source cable AP remains plugged in the ac outlet AS. The on-state or off-state of a power source of a personal computer realizing each client is determined with a power source switch PS on each client C (device). The power source of the client C is in off-state unless it is being used.
The server performs various kinds of maintenance on a specified client, through remote control, when the client is not being used and the power source thereof is in off-slate (in the nighttime). At this time, the power source switch on the client must be turned on in order to perform maintenance on the client. Therefore, the server transmits a wake-up packet WP (corresponding to an activating signal that will be described later) to the specified client. The wake-up picket is structured based on a specific packet format, and defined as a packet that, when the client receives the packet, turns on the power source of the client. The wake-up packet is transmitted to the specified client via the hub. When the power source switch on the client is in off-state, if the client receiver the wake-up packet, the client turns on the power source switch thereon automatically. Thereafter, software is upgraded or various kinds of information are transferred between the server and client.
A block diagram showing the internal configurations of a conventional client and a conventional hub, is illustrated in FIG. 2. Further, a timing chart for explaining the conventional sequence of the delivery of power sources, is illustrated in FIG. 3. Shown in FIG. 2 are the practical configurations of a conventional client and a conventional hub included in a LAN control system.
As shown in FIG. 2, tho conventional client C mainly comprises a power source circuit 6 that generates electric power for the client, a circuit portion 4 including a CPU (central processing unit), a memory, and a chip set, and a LAN control circuit 1 including a LAN chip that controls a LAN. The power source circuit 6 receives ac power by way of an ac power source cable AP, internally converts the ac power to direct current (dc) power, supplies a first power source P-1 to the circuit portion 4 including the CPU, and supplies second power source P-2 to the LAN control circuit 1.
Referring to the timing chart of FIG. 3, a description will be made regarding the sequence of the delivery of power sources in the client or hub. Normally, the ac power source cable is left plugged into the ac outlet, and an ac power source is always set to an on-state level ((1) in FIG. 3). The delivery of the first power source P-1 and a second power source P-2 is controlled by the power source switch PS ((2) in FIG. 2). When the power source switch PS is in on-state, that is, when the client is used, the first power source P-1 is delivered. When the power source switch PS is in off-state, that is, the client is unused, the first power source P-1 is not delivered ((3) in FIG. 3). On the other hand, the power source circuit 6 must keep delivering the second power source P-2 to the LAN control circuit 1 so that the LAN control circuit can receive the wake-up packet from the server 5 even when the client is unused. When ac power is having supplied, the second power source P-2 is Ret to the on-state level irrespective of whether the power source switch PS is turned on or turned off ((4) in FIG. 3). Furthermore, the third power source P-3 delivered from a power source circuit 19 incorporated in the hub H is get to the on-state level, irrespective of whether the power source switch PS in turned on or turned off ((5) in FIG. 3). This is intended to allow the hub h to receive the wake-up packet from the server S.
The power source circuit 6 delivers the first power source P-1 to the circuit portion 4 including the CPU, memory, and chip set. When user uses the client personal computer (when the power source switch PS is turned on), the circuit portion 4 is activated and put into operation. In this case, the circuit portion 4 is connected to the LAN control circuit 1 over a personal computer interface (PCT) bus 5. When a user uses the client personal computer, the user may insert a storage medium 40, such as a hard disk or a magneto-optical disk, into a slot in the personal computer so as to start up the personal computer. The second power source P-2 is delivered from the power source circuit 6 to the LAN control circuit 1, which is realized with a LAN chip, through a Vcc pin. When the ac power is supplied to the client, the second power source P-2 is set to the on-state level, irrespective of the state of the power source switch PS.
Furthermore, the LAN control circuit 1 includes a wake-up packet monitor unit 10 (corresponding to an activating signal monitor unit included in a separate device that will be described later). The wake-up packet monitor unit 10 monitors a packet received by a reception unit 3 included in the LAN control circuit so as to check if the packet is a wake up packet. As the wake-up packet, a magic packet structured based on a special format is adopted. If the received packet is the wake-up packet, the fact is reported to the outside using a wake-up signal 12. The wake-up signal 12 is combined with a PME# signal on the PCI bus, undergoes a logical sum (i.e., logical OR) with A power on/off signal sent from the power source switch PS, and then applied to the power source circuit 6. The active state of the power source circuit 6 is initiated with a press of the power source switch PS or the application of the PME# signal. The inactive state of the power source circuit 6 is initiated by turning off the power source switch PS, but is not initiated with the PME# signal ((6) in FIG. 3).
The client and hub H shown in FIG. 2 are physically interconnected by way of a 10 Base-T or 100 Base-TX twisted-pair cable TC. Over tho twisted-pair cable, a TX+/xe2x88x92 signal produced by a transmission unit 2 incorporated in the LAN control circuit and an RX+/xe2x88x92 signal produced by a reception unit 16 incorporated in a transmission/reception circuit 26 in the hub, are combined with each other. Moreover, a TX+/xe2x88x92 signal produced by a transmission unit 17 incorporated in the transmission/reception circuit 26 in the hub and an RX+/xe2x88x92 signal produced by a reception unit 3 incorporated in the client, are combined with catch other ((7) and (8) in FIG. 3).
The logical connection between the LAN control circuit 1 and hub H is attained with establishment of a link. Over a transmission line, a link signal 13 is superposed on the TX+/xe2x88x92 signal produced by the client, and the hub identities the link signal 13. Over a reception line, when the hub receives a wake-up packet, a link signal 14 is superposed on the TX+/xe2x88x92 signal produced by the hub, and the client identifies the link signal 14. When both the link signals 13 and 14 are identified, a link is established. The link signals 13 and 14 are produced respectively with the LAN control circuit 1 in the client activated and with the power source of the hub turned on. Normally, the link is left established.
The link signal is a pulsating signal transmitted over a LAN at intervals of a certain time or cycle. The 10 Base-T or 100 Base-TX protocol is adopted as a standard rule.
The wake-up packet is transmitted from the server to the client via the hub in the state that a link is established between the LAN control circuit 1 and hub. The LAN control circuit 1 must therefore be able to receive the wake-up packet from the server all the time. The second power source P-2 is therefore delivered to the LAN control circuit 1 in order to keep the link established all the time.
As mentioned above, in the conventional LAN control system, maintenance of each client by a server is performed in the nighttime when a user is absent. In this case, the server performs maintenance on clients in order. The clients must therefore be able to receive a wake-up packet from the server all the time. The LAN control circuit incorporated in each client must always be active and the power source of a hub must always be in the on-state. However, in reality, only when maintenance is performed, must the LAN control circuit be active and the power source be in on-state. This poses a problem in which electric power is unnecessarily wasted.
In Japanese Unexamined Patent Application Publication (Kokai) No. 7-115428 (published on May 2, 1995) that is the first related art concerning the conventional LAN control system, a remote power source control method has been disclosed. According to the remote power source control method, a remote power source control unit 200 that operates with an auxiliary power source 310 (equivalent to the second power source in FIG. 2) is included in a plurality of information processing devices that is interconnected over a network. Based on data received by the remote power source control unit 200, the delivery of main power source 300 in each information processing device (equivalent to the first power source in FIG. 2) is controlled to be continued or discontinued.
In the foregoing remote power source control method, a remote power source control can be achieved independently of a network architecture, and a security check can be performed reliably. However, according to the above method, the auxiliary power source 310 must always be set to an on-state level in order to allow the information processing device to stand by for a wake-up packet. Therefore, the aforesaid problem in which electric power is unnecessarily wasted in order to allow a device to stand by for a wake-up packet remains unsolved.
In Japanese Unexamined Patent Application Publication (Kokai) No. 6-67762 (published on Mar. 11, 1994) that is the second related art concerning the conventional LAN control system, the configuration of an automatic power source control device for an information processing terminal has been disclosed. The automatic power source control device operates with the delivery of a main power source 6 within a certain workstation. The automatic power source control device includes a main CPU 1 and a first sub CPU 2 that execute predetermined terminal processing jobs, and a second sub CPU 3 that receives another dedicated power source 7. In a stand-by mode in which the delivery of the main power source is discontinued, when the second sub CPU 3 receives and interprets a command for turning on a power source from another workstation, a power source control unit 4 delivers the main power source 6. Thereafter, the second sub CPU 3 passes LAN control to the first sub CPU 2.
In the foregoing configuration, a plurality of CPUs is used to control, that is, continue or discontinue the delivery of the main power source in the stand-by mode, in order to reduce electric power that is to be consumed in the standby mode. However, even in this configuration, the power source that is to be delivered to the CPU must be set to the on-state level all the time so that the information processing terminal can stand by for a wake-up packet. The aforesaid problem in which electric power is unnecessarily wasted in order to allow a device to stand by for a wake-up packet remains unsolved.
In short, in order to receive a wake-up packet, only when the wake-up packet is transmitted from a server, the power sources of a client and a hub may be turned on. In the related arts including the aforesaid related arts, however, electric power must be delivered to a LAN control circuit incorporated in the client and to the hub all the time.
Accordingly, the present invention attempts to solve the foregoing problems. An object of the present invention is to provide a network control system, a network apparatus, a repeater, and a connecting apparatus. In the network control system, electric power is delivered to a LAN control circuit incorporated in each client and to a hub only when electric power is needed in order to receive a wake-up packet from a server. Thus, the consumption of unnecessary electric power is suppressed.
In order to solve the aforesaid problems, according to the present invention, there is provided a network control system including a managing device, separate devices that communicate with the managing device and a repenter for interconnecting the managing device to the separate devices. The power source switch on a separate device that has received an activating signal sent from the managing device via the repeater is turned on, and the managing device performs various kinds of maintenance on the separate device. In such a network control system, each separate device includes a power source control circuit that controls the on-state and off-state levels of a power source which is to be delivered to a circuit including at least a separate device side activating signal monitor unit which monitors whether or not the activating signal has been received. Owing to the power source control circuit, when it is detected that the power source switch is in off-state, the transmission of a predetermined signal to the repeater is suppressed.
Preferable, when the repeater detects that a separate device has stopped transmitting the predetermined signal, the repeater stops transmitting a signal which indicates the reception of the predetermined signal, to the separate devise.
More preferably, when a separate device detects that the repeater has stopped transmitting the signal which indicates the reception of the predetermined signal, the separate device sets a power source which is to be delivered to the separate device side activating signal monitor unit, to an off-state level.
According to the present invention, there is provided a network apparatus having a power source switch thereof turned on when receiving an activating signal sent from a managing device via a repeater over a network. Various kinds at maintenance is performed on the device by the managing device. The device includes a power source control circuit that controls the on-state and off-state levels of a power source which is to be delivered to a circuit including at least an activating signal monitor unit which monitors whether or not the activating signal has been received. Owing to the power source control circuit, when it is detected that the power source switch is in off-state, the transmission of a predetermined signal to the repeater is suppressed.
Preferably, when the predetermined signal is not transmitted to the repeater any longer, if it is detected that the repeater has stopped transmitting a signal which indicates the reception of the predetermined signal, the power source control circuit sets a power source which is to be delivered to the activating signal monitor unit, to the off-state level.
More preferably, when the repeater notifies that it has detected the reception of the activating signal from the managing device, the power source control circuit sets a power source which is to be delivered to the circuit, including at least the activating signal monitor unit, to the on state level.
More preferably, in the network apparatus in accordance with the present invention, after the power source that is to be delivered to the circuit, including at least the activating signal monitor unit, is set to the on-state level, the predetermined signal is retransmitted to the repeater.
According to the present invention, there is provided a repeater which interconnects a managing device with separate devices, which communicate with the managing device, over a network. On receipt of an activating signal sent from the managing device, the repeater allows the managing device to perform various kinds of maintenance on each of the separate devices. The repeater includes an activating signal monitor unit and a power source control circuit. The activating signal monitor unit monitors whether or not the activating signal has been received. Based on a signal sent from the activating signal monitor unit, the power source control circuit controls the on-state and off-state levels of a power source which is to be delivered to a transmission/reception circuit that transfers various signals to or from each of the separate devices. When the transmission/reception circuit detects that a given separate device has stopped transmitting a predetermined signal, the power source control circuit sets the power source which is to be delivered to the transmission/reception circuit, to the off-state level. The transmission/reception circuit stops transmitting a signal which indicates reception of the predetermined signal, to the given separate device.
Preferably, when the activating signal monitor unit detects the reception of the activating signal, the power source control circuit sets the power source which is to be delivered to the transmission/reception circuit, to the on-state level. The transmission/reception circuit transmits the signal which indicates reception of the activating signal, to the given separate device.
More preferably, after the transmission/reception circuit transmits the signal which indicated reception of the activating signal, to the given separate device, when the transmission/reception circuit detects that the given separate device has retransmitted the predetermined signal, the transmission/reception circuit retransmits the signal which indicates the reception of the predetermined signal, to the given separate device.
According to the present invention, there is provided a connecting apparatus for connecting a network apparatus, which has a power source switch thereof turned on when receiving an activating signal sent from a managing device via a repeater over a network and on which the managing device performs various kinds of maintenance, onto the network. The connecting apparatus includes a power source control circuit that controls the on-state and off-state levels of the power source which is to be delivered to a circuit including at least an activating signal monitor unit which monitors whether or not the activating signal has been received. Owing to the power source control circuit, when it is detected that the power source is in off-state, the transmission of a predetermined signal to the repeater is suppressed.
Preferably, when the predetermined signal is not transmitted to the repeater any longer, if it is detected that the repeater has stopped transmitting a signal which indicates the reception of the predetermined signal, the power source control circuit sets the power source which is to be delivered to the activating signal monitor unit, to the off-state level.
More preferably, when the repeater notifies that it has detected the reception of the activating signal sent from the managing device, the power source control circuit sets the power source which is to be delivered to the circuit including at least the activating signal monitor units to the on-state level.
More preferably, in the network connecting block in accordance with the present invention, after the power source which is to be delivered to the circuit including at least the activating signal monitor unit is set to the on-state level, the predetermined signal is retransmitted to the repeater.
More particularly, in an LAN control system that is an example of a network control system in accordance with the present invention, the power source switch of a client having received a wake-up packet from a server via a hub is turned on automatically, and the server performs various kinds of maintenance on the client. In this case, the client includes a client side power source control circuit that controls the on-state and off-state levels of a power source which is to be delivered to a circuit including at least a client side wake-up packet monitor unit which monitors whether or not the wake-up packet has been received. When detecting that the power source switch is in off-state, the client side power source control circuit suppresses the transmission of a predetermined signal to the hub.
Preferably, when the hub included in the LAN control system in accordance with the present invention detects that the client has stopped transmitting the predetermined signal, the hub transmits a signal which indicates the reception of the predetermined signal, to the client.
More preferably, when a client included in the LAN control system in accordance with the present invention detects that the hub has stopped transmitting the signal indicating the reception of the predetermined, the client sets the power source which is to be delivered to the client side wake-up packet monitor unit, to the off-state level.
A LAN client in accordance with the present invention includes a client side power source control circuit which controls the on-state and off-state levels of the power source which is to be delivered to a circuit including at least a client side wake-up packet monitor unit which monitors whether or not a wake-up packet has been received. Owing to the power source control circuit, when it is detected that a power source switch is in off-state, the transmission of a predetermined signal to a hub is suppressed.
Preferably, in the client in accordance with the present invention, when the predetermined signal is not transmitted to the hub any longer, if it is detected that the hub has stopped transmitting the signal which indicates the reception of the predetermined signal, the client side power source control circuit sets the power source which is to be delivered to the client side wake-up packet monitor unit, to the off-state level.
More preferably, in the client in accordance with the present invention, when the hub notifies that the hub has detected the reception of the wake-up packet frown the server, the client side power source control circuit sets the power source which is to be delivered to the circuit, including at least the client side wake-up packet monitor unit, to the on-state level.
More preferably, in the client in accordance with the present invention, after the power source which is to be delivered to the circuit, including at least the client side wake-up packet monitor unit, is set to the on-state level, the-predetermined signal is retransmitted to the hub.
A LAN hub in accordance with the present invention includes a hub side wake-up packet monitor unit and a hub side power source control circuit. The hub side wake-up packet monitor unit monitors whether or not a wake-up packet has been received. Based on a signal sent from the wake-up packet monitor unit, the hub side power source control circuit controls the on-state and off-state levels of the power source which is to be delivered to a transmission/reception circuit which transfers various signals to or from a client. When the transmission/reception circuit detects that the client has stopped transmitting a predetermined signal, the power source control circuit rats the power source which is to be delivered to the transmission/reception circuit, to the off-state level. The transmission/reception circuit stops transmitting a signal which indicates the reception of the predetermined signal, to the client.
Preferably in the hub in accordance with the present invention, when the hub side wake-up packet monitor unit detects the reception of the wake-up packet, the hub side power source control circuit sets the power source which is to be delivered to the transmission/reception circuit, to the on-state level. The transmission/reception circuit transmits a signal which notifies that the wake-up packet has been received, to the client.
More preferably, in the hub in accordance with the present invention, after the transmission/reception circuit transmits the signal which notifies that the wake-up packet has been received, to the client, when the client retransmits the predetermined signal, the transmission/reception circuit retransmits the signal which indicates the reception of the predetermined signal, to the client.
There is provided a storage medium that is computer-readable and is used to start up a personal computer realizing a client in accordance with the present invention. Means stored in the storage medium include a means for turning on the power source switch of a client on receipt of a wake-up packet sent from a server via a hub over a LAN; a means for controlling the on-state and off-state levels of a power source which is to be delivered to a circuit including at least a client side wake-up packet monitor unit which monitors whether or not the wake up packet has been received; and a means for, when it is detected that the power source switch is in off-state, suppressing the transmission of a predetermined signal to the hub.
In short, according to the present invention, when the power source switch of a client is in off-state, a power source control circuit included in the client (a separate device), and a wake-up packet monitor unit (activating signal monitor unit) and a power source control circuit included in a hub (repeater) are used to deactivate a LAN control circuit (connecting apparatus) realized with a LAN chip and turn off the power source of the hub unless the LAN control circuit and hub are needed. Thus, electric power which is to be consumed by the client and hub is saved. When a server (managing device) transmits a wake-up packet (activating signal), the LAN control circuit included in thy client is activated and the power source of the hub is turned on so that the LAN control circuit and hub can receive a wake-up packet.
As mentioned above, according to the present invention, electric power can be supplied to the LAN control circuit included in the client and to the hub only when the electric power is needed in order to receive a wake-up packet from the server. The consumption of unnecessary electric power can be suppressed.